Welded transmission rod machining method for controlling initial unbalance

Abstract

The invention belongs to the technical field of aero-engines, and provides a welding type transmission rod machining method for controlling the initial unbalance amount, a welding type transmission rod comprises a first transmission rod and a second transmission rod, and the method comprises the steps that a positioning spigot is formed in the welding end of the first transmission rod or the second transmission rod; a to-be-welded transmission rod is formed through connection of a positioning spigot, and a mandrel penetrates into the to-be-welded transmission rod and is axially fixed through a bolt assembly to form a to-be-welded assembly; vacuumizing treatment is conducted in a vacuum environment, the positioning seam allowance is welded and fixed in a vacuum electron beam welding mode, and after welding is completed, the positioning seam allowance is removed, and the mandrel is taken out; machining an initial spline and carrying out cyaniding heat treatment; and sequentially carrying out outer diameter finish machining, spline outer diameter coping and spline inner diameter finish machining on the transmission rod subjected to cyaniding heat treatment to obtain the final transmission rod. According to the method, the deformation influence caused by hot working such as welding and cyaniding of the welding type transmission rod can be reduced to the minimum, and the low initial unbalance amount is obtained.

Description

Technical Field

[0001] The present invention belongs to the technical field of aero-engines and relates to a processing method for a welded transmission rod for controlling the initial unbalance amount. Background Art

[0002] The transmission rod in an aero-engine is slender and has a high rotational speed. To improve its vibration margin, the central transmission rod is often thickened, and under the condition that the spline parameters at both ends remain unchanged, a large-diameter surface, a variable cross-section at the upper part, and a variable cross-section at the lower part are formed. To realize the structure, the middle transmission rod is usually designed into upper and lower ends and connected by welding.

[0003] During the processing of the transmission rod, two important hot processes are required, and the transmission rod is deformed during both hot processes. Currently, hot-state straightening or no deformation control is often adopted, and only the material removal operation is carried out at both ends of the transmission rod to control the structural unbalance amount. However, for a thin-walled and long transmission rod, due to its poor stiffness, it is difficult to meet the high-precision unbalance amount requirement. Summary of the Invention

[0004] In order to solve the technical problem that it is difficult to control the unbalance amount due to the poor stiffness of the thin-walled and long transmission rod, the present invention discloses a processing method for a welded transmission rod for controlling the initial unbalance amount. The welded transmission rod includes a first transmission rod and a second transmission rod. The method includes the following steps:

[0005] S1. Machining allowances are provided at the inner holes of the spline ends of the first transmission rod and the second transmission rod, and a positioning stop is provided at the welding end of the first transmission rod or the second transmission rod.

[0006] S2. The first transmission rod and the second transmission rod are connected through the positioning stop to form a transmission rod to be welded. A mandrel is inserted into the transmission rod to be welded and axially fixed through a bolt assembly to form an assembly to be welded. Among them, an exhaust channel communicating with the outside is provided on the mandrel near the positioning stop.

[0007] S3. The assembly to be welded is placed in a vacuum environment for vacuuming, and the positioning stop is welded and fixed by a vacuum electron beam welding method. After welding, the positioning stop is removed and the mandrel is taken out to obtain a welded transmission rod.

[0008] S4. Initial splines are machined at both ends of the welded transmission rod, and the initial spline tooth surfaces are subjected to cyaniding heat treatment.

[0009] S5. The outer diameter of the transmission rod after cyaniding heat treatment is finely machined, the outer diameter of the spline is ground, and the inner diameter of the spline is finely machined in sequence to obtain the final transmission rod.

[0010] Further, the splined ends of the first transmission rod and the second transmission rod have small-diameter inner holes, and the welding ends have large-diameter inner holes.

[0011] Further, the length of the mandrel is greater than the length of the welded transmission rod. A shoulder is provided at one end of the mandrel close to the positioning stop, and an external thread for installing the bolt assembly is provided at the end away from the positioning stop.

[0012] Further, the first transmission rod and the second transmission rod have different lengths.

[0013] Further, a rough machining reference surface is provided at the end of the transmission rod weldment and close to the positioning stop, and splines are machined at both ends of the transmission rod weldment according to the rough machining reference surface.

[0014] Further, before the cyanide heat treatment of the spline tooth surface, plugging members are provided at the inner holes at both ends of the transmission rod weldment to prevent the inner holes of the transmission rod from being cyanided for protection. After the cyanide heat treatment of the transmission rod, it is hoisted to release the thermal stress.

[0015] Further, in step S5, finish machining the outer diameter of the transmission rod after cyanide heat treatment, including:

[0016] S51. Finish machine the outer diameter of the transmission rod after cyanide heat treatment according to the designed dimension of the outer diameter of the transmission rod;

[0017] S52. According to the thermal deformation analysis, select a position with the least thermal deformation as the combined reference surface for finish machining at the welding ends of the first transmission rod and the second transmission rod, and at the variable diameter positions of the inner holes of the spline end and the welding end respectively;

[0018] S53. According to the combined reference surface, grind the splines and finish machine the outer diameter of the transmission rod. Finish machine the inner hole of the spline based on the designed dimension of the inner hole of the spline with the outer circle of the ground spline as the reference. After the finish machining of the inner hole of the spline, perform dynamic balancing to remove materials.

[0019] The processing method of the present invention can minimize the deformation effects brought by hot processing such as welding and cyaniding of the welded transmission rod, and obtain a lower initial unbalance. Description of the Drawings

[0020] In order to more clearly illustrate the technical solutions of the embodiments of the present application, the drawings required for use in the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present application. For those of ordinary skill in the art, other drawings can be obtained based on these drawings without creative efforts.

[0021] Figure 1Flow chart of the processing method for the welded drive rod to control the initial unbalance amount disclosed in the embodiments of the present invention;

[0022] Figure 2 Schematic diagram of the welded drive rod disclosed in the embodiments of the present invention;

[0023] Figure 3 Schematic diagram of the components to be welded disclosed in the embodiments of the present invention;

[0024] Figure 4 Schematic diagram of the drive rod hoisting to release thermal stress disclosed in the embodiments of the present invention;

[0025] Wherein, 1, the first drive rod; 2, the second drive rod; 3, the first spline; 4, the second spline; 6, the first variable cross-section; 7, the second variable cross-section; 8, the first material removal position; 9, the second material removal position; 10, the positioning stop; 12, the mandrel; 13, the bolt assembly; 14, the shoulder; 15, the exhaust passage; 16, the first plugging member; 17, the first plugging member; 18, the counterweight; 19, the rope. Detailed implementation manners

[0026] The embodiments of the present application will be described in detail below with reference to the accompanying drawings.

[0027] The following illustrates the implementation manners of the present application through specific specific examples. Those skilled in the art can easily understand other advantages and effects of the present application from the content disclosed in this specification. Obviously, the described embodiments are only a part of the embodiments of the present application, rather than all of the embodiments. The present application can also be implemented or applied through other different specific implementation manners. Various details in this specification can also be modified or changed based on different viewpoints and applications without departing from the spirit of the present application. It should be noted that, without conflict, the following embodiments and the features of the embodiments can be combined with each other. All other embodiments obtained by those of ordinary skill in the art based on the embodiments in the present application without creative efforts belong to the scope of protection of the present application.

[0028] The embodiments of the present invention disclose a processing method for a welded drive rod to control the initial unbalance amount. Refer to Figure 2 As shown, the welded drive rod includes a first drive rod 1 and a second drive rod 2. In implementation, the first drive rod 1 can also be called the upper drive rod, and the second drive rod 2 can also be called the lower drive rod. The spline ends of the first drive rod 1 and the second drive rod 2 are small-diameter inner holes, and the welding ends are large-diameter inner holes. The final drive rod can be obtained by assembling, welding, processing, and grinding the first drive rod 1 and the second drive rod 2. The lengths of the first drive rod 1 and the second drive rod 2 are different. For example, the first drive rod 1 can be set as a long drive rod, and the second drive rod 2 can be set as a short drive rod.

[0029] See Figure 1 As shown, the processing method of the welded transmission rod includes the following steps:

[0030] S1. Processing allowances are provided at the inner holes of the spline ends of the first transmission rod 1 and the second transmission rod 2, and a positioning stop 10 is provided at the welding end of the first transmission rod 1 or the second transmission rod 2;

[0031] S2. Connect the first transmission rod 1 and the second transmission rod 2 through the positioning stop 10 to form a transmission rod to be welded, and insert a mandrel 12 into the transmission rod to be welded and axially fix it through a bolt assembly to form an assembly to be welded. Among them, an exhaust passage 15 communicating with the outside is provided on the mandrel 12 near the positioning stop 10;

[0032] S3. Place the assembly to be welded in a vacuum environment for vacuuming, and weld and fix the positioning stop 10 by vacuum electron beam welding. After welding, remove the positioning stop 10 and take out the mandrel 12 to obtain a welded transmission rod;

[0033] S4. Process the initial splines at both ends of the welded transmission rod, and perform cyaniding heat treatment on the tooth surfaces of the initial splines;

[0034] S5. Perform finish machining on the outer diameter, grinding on the outer diameter of the spline, and finish machining on the inner diameter of the spline of the transmission rod after cyaniding heat treatment in sequence to obtain the final transmission rod.

[0035] Furthermore, when implementing the above step S1, processing allowances are provided at the inner holes of the spline ends. See Figure 2 As shown, processing allowances can be left at the inner hole ΦM position of the first spline 3 and the inner hole ΦN position of the second spline 4, so as to ensure the wall thickness of the spline by grinding the allowances after all hot processing is completed, and compensate for the deformation of the spline caused by hot processing.

[0036] At the same time, before welding, a positioning stop 10 is provided at the welding end of the first transmission rod 1 or the second transmission rod 2. See Figure 3 As shown, a positioning stop 10 can be provided on a short transmission rod such as the second transmission rod 2. By adjusting the fit tolerance of the stop position to an interference fit and using hot fitting for assembly, it is ensured that the two parts are concentric during welding.

[0037] Further, when implementing the above step S2, in order to ensure that the first transmission rod 1 and the second transmission rod 2 are concentric during the welding process, the mandrel 12 is inserted into its inner core for axial positioning. The length of the mandrel 12 is greater than the length of the welded transmission rod. One end of the mandrel 12 near the positioning stop has a shoulder 14, and the other end far from the positioning stop has an external thread for installing the bolt assembly 13. The diameter requirement of the exhaust passage 15 on the mandrel 12 is not less than The exhaust passage 15 enables the welding position inside the component to be welded to communicate with the outside, ensuring that the internal and external pressure differences are the same.

[0038] In addition, when implementing, the mandrel 12 has a small clearance fit at the inner hole ΦM position of the first spline 3 and the inner hole ΦN of the second spline 4, improving the axial support effect of the mandrel 12. See Figure 3 As shown, after the mandrel 12 is installed into the transmission rod to be welded, the bolt assembly 13 is pressed axially and circumferentially braked to reduce the deformation caused by the movement of the upper transmission rod and the lower transmission rod during welding.

[0039] Further, when implementing the above step S3, before welding, vacuum pumping is first carried out in a vacuum environment so that the axis of the transmission rod before welding is completely evacuated. After welding is completed, the mandrel 12 can be taken out to obtain the welded transmission rod for subsequent processing.

[0040] Further, when implementing the above step S4, see Figure 2 As shown, a rough machining reference surface A can be set at the end of the welded transmission rod and near the positioning stop 10. The rough machining reference surface A can be a position on the first transmission rod 1 with less heat influence. According to the rough machining reference surface, splines are machined at both ends of the welded transmission rod, and the machined splines are subjected to cyanide heat treatment. When implementing, the distance between the rough machining reference surface A and the weld can be designed to be greater than or equal to 15 mm. When machining, a small amount of machining allowance should be left on the outer diameter of the spline, and the allowance is 0.5 - 1.5 mm. After all hot working is completed, the deformation of the outer diameter of the spline is corrected.

[0041] Before cyanide heat treatment, in order to prevent the inside of the transmission rod from being cyanided, see Figure 4 As shown, a first plugging member 16 can be set at the spline end of the first transmission rod 1, and a second plugging member 17 can be set at the spline end of the second transmission rod 2. The first plugging member 16 and the second plugging member 17 can be selected as welding blocks and welded in the holes. After cyanide heat treatment, a rope 19 can be used for hoisting, and a counterweight 18 with a weight of not less than 1 KG can be set at the lower end of the second transmission rod 2 to release the thermal stress during hoisting of the transmission rod.

[0042] Further, the outer diameter of the transmission rod after cyanide heat treatment is finely machined, including:

[0043] S51. Finish machining the outer diameter of the transmission rod after cyaniding heat treatment according to the designed dimensions of the outer diameter of the transmission rod.

[0044] S52. According to the thermal deformation analysis, at the welding ends of the first transmission rod 1 and the second transmission rod 2, and near the variable diameter positions of the inner hole of the spline end and the inner hole of the welding end, respectively select a position with the smallest thermal deformation as the finish machining reference surface.

[0045] S53. According to the combined reference surface, grind the spline and finish machine the outer diameter of the transmission rod. With the outer circle of the ground spline as the reference, finish machine the inner hole of the spline according to the designed dimensions of the inner hole of the spline. After the finish machining of the inner hole of the spline, perform dynamic balancing to remove materials. By finish machining the inner hole of the spline, the wall thickness at the spline can be made uniform. As shown in the figure, a first material removal position 8 is provided on the first transmission rod 1, and a second material removal position 9 is provided on the second transmission rod 2. Figure 4 As shown in the figure, a first material removal position 8 is provided on the first transmission rod 1, and a second material removal position 9 is provided on the second transmission rod 2.

[0046] When the above step S5 is specifically implemented, as shown in the figure, the finish machining reference surface B and the finish machining reference surface C with less influence of thermal deformation can be selected as the machining reference to complete the finish machining of the entire rough machining reference surface A, complete the machining of all outer diameter surface dimensions based on the rough machining reference surface A, and finally complete the final machining of the inner hole dimensions based on the outer diameters of the tooth surfaces of the first spline 3 and the second spline 4 of the spline. Figure 2 As shown in the figure, the finish machining reference surface B and the finish machining reference surface C with less influence of thermal deformation can be selected as the machining reference to complete the finish machining of the entire rough machining reference surface A, complete the machining of all outer diameter surface dimensions based on the rough machining reference surface A, and finally complete the final machining of the inner hole dimensions based on the outer diameters of the tooth surfaces of the first spline 3 and the second spline 4 of the spline.

[0047] When selecting the finish machining reference surface B and the finish machining reference surface C, as shown in the figure, the finish machining reference surface B can be close to the first variable cross-section 6 of the first transmission rod 1, and the distance between the two can be set to 10 - 20 mm. The finish machining reference surface C can be close to the second variable cross-section 7 of the second transmission rod 2, and the distance between the two can be set to 10 - 20 mm. Figure 2 As shown in the figure, the finish machining reference surface B can be close to the first variable cross-section 6 of the first transmission rod 1, and the distance between the two can be set to 10 - 20 mm. The finish machining reference surface C can be close to the second variable cross-section 7 of the second transmission rod 2, and the distance between the two can be set to 10 - 20 mm.

[0048] The processing method of the present invention can minimize the deformation influence brought by hot processing such as welding and cyaniding of the welded transmission rod, and obtain a lower initial unbalance amount.

[0049] Obviously, the above are only the preferred embodiments of the present invention and are not used to limit the present invention. For those skilled in the art, various changes and modifications can be made to the embodiments of the present invention. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present invention shall be included within the protection scope of the present invention.

Claims

1. A processing method for a welded drive rod to control the initial unbalance amount, the welded drive rod comprising a first drive rod (1) and a second drive rod (2), characterized in that, The method includes: Machining allowances are provided at the inner holes of the spline ends of the first transmission rod (1) and the second transmission rod (2), and a positioning stop (10) is provided at the welding end of the first transmission rod (1) or the second transmission rod (2); The first transmission rod (1) and the second transmission rod (2) are connected through the positioning stop (10) to form a transmission rod to be welded. A mandrel (12) is inserted into the transmission rod to be welded and axially fixed through a bolt assembly to form an assembly to be welded. Wherein, an exhaust passage (15) communicating with the outside is provided on the mandrel (12) near the positioning stop (10); The assembly to be welded is placed in a vacuum environment for vacuuming, and the positioning stop (10) is welded and fixed by vacuum electron beam welding. After welding, the positioning stop (10) is removed and the mandrel (12) is taken out to obtain a welded transmission rod; Initial splines are machined at both ends of the welded transmission rod, and the surfaces of the initial spline teeth are subjected to cyaniding heat treatment; The outer diameter of the transmission rod after cyaniding heat treatment is finely machined, the outer diameter of the spline is ground, and the inner diameter of the spline is finely machined in sequence to obtain the final transmission rod.

2. The processing method of the welded transmission rod for controlling the initial unbalance amount according to claim 1, characterized in that, The spline ends of the first transmission rod (1) and the second transmission rod (2) are small-diameter inner holes, and the welding ends are large-diameter inner holes.

3. The processing method of the welded drive rod for controlling the initial unbalance amount according to claim 1, characterized in that, The length of the mandrel (12) is greater than the length of the welded transmission rod. A shoulder (14) is provided at one end of the mandrel (12) near the positioning stop, and an external thread for installing the bolt assembly is provided at the other end away from the positioning stop.

4. The processing method of the welded transmission rod for controlling the initial unbalance amount according to claim 1, characterized in that, The lengths of the first transmission rod (1) and the second transmission rod (2) are different.

5. The processing method of the welded transmission rod for controlling the initial unbalance amount according to claim 1, characterized in that, A rough machining reference surface is set at the end of the welded transmission rod and near the positioning stop (10), and splines are machined at both ends of the welded transmission rod according to the rough machining reference surface.

6. The processing method of the welded transmission rod for controlling the initial unbalance amount according to claim 1, characterized in that, Before the cyaniding heat treatment of the spline tooth surface, blocking members are provided at the inner holes at both ends of the welded transmission rod, and the welded transmission rod after cyaniding heat treatment is hoisted to release thermal stress.

7. The processing method of the welded transmission rod for controlling the initial unbalance amount according to claim 1, characterized in that, The fine machining of the outer diameter of the transmission rod after cyaniding heat treatment includes: According to the designed dimension of the outer diameter of the transmission rod, the outer diameter of the transmission rod after cyaniding heat treatment is finely machined; According to the thermal deformation analysis, at the welding ends of the first transmission rod (1) and the second transmission rod (2), and near the variable diameter positions of the inner hole of the spline end and the inner hole of the welding end, a position with the smallest thermal deformation is respectively selected as the combined reference surface for fine machining; According to the combined reference surface, the spline is ground and the outer diameter of the transmission rod is finely machined. Based on the outer circle of the ground spline, the inner hole of the spline is finely machined according to the designed dimension of the inner hole of the spline. After the fine machining of the inner hole of the spline, dynamic balance material removal treatment is carried out.

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